Motor control with clutch and brake assembly



June 21, 1966 L. M, u sT 3,256,963

MOTOR CONTROL WITH CLUTCH AND BRAKE ASSEMBLY Original Filed June 6, 196075 7f VENTOR.

Mke/YA ZMBZ JWQMMdJ/? United States Patent 3,256,963 MOTOR CONTROL WITHCLUTCH AND BRAKE ASSEMBLY Leslie M. Hurst, Princeton, Ind., assignor toHurst Mfg. Corp., a corporation of Indiana Continuation of applicationSer. No. 34,258, June 6, 1960.

This application Mar. 20, 1964, Ser. No. 354,505

4 Claims. (Cl. 192.072)

This application is a continuation of application Serial No. 34,258,filed June 6, 1960 now abandoned and entitled Clutch.

This invention relates to a novel combination clutch and brake assemblyfor use with a fractional horsepower electric motor.

Fractional horsepower electric motors are used in many applicationsrequiring the output speed of a fractional horsepower motor to bereduced through a gear train, and, in certain applications, requiringthe driven member to stop and start as desired. "A simple clutch whichconnects the motor with the driven device and disconnects it as desiredis suitable for some applications; however, in certain application, itis particularly desirable to stop the driven device instantaneously. Inthese applications; it is not sufiicient to simply de-energize the motorbecause the inertia of the motor rotor continues to drive the drivendevice after the source of power-is cut off, and the inertia of thedriven device also requires time to be dissipated. Therefore, it is anobject of the present invention to provide a novel clutch and breakassembly for use with a fractional horsepower motor in which the clutchmechanically disconnects the motor rotor from a driven device andessentially simultaneously applies to brake to stop the driven device.

It is another object of the hereindisclosed invention to provide animproved combination clutch and brake for use with a fractionalhorsepower motor which clutch and'brake combination may be mounted onthe fractional horsepower motor.

A further object of the present invention is to provide a clutch andbrake combination which reacts rapidly to actuation, is inexpensive tomanufacture, and has a high degree of reliability.

The aforementioned objects of the herein disclosed invention andadditional objects will be readily understood and appreciated by thoseskilled in the art from a further reading of the present disclosure;particularly when viewed in light of the drawings, in which:

FIGURE 1 is a plan view of a gear train having a combiuation clutch andbrake embodying the herein disclosed invention mounted on a fractionalhorsepower motor;

FIGURE 2 is a sectional view taken on line 22 of FIGURE 1 showing thegear arrangements;

FIGURE 3 is an enlarged sectional view of a combination clutch and brakein a driving attitude taken on line 33 of FIGURE 1; and

FIGURE 4 is a sectional view of the combination clutch and 'brake shownin FIGURE 3 but with the clutch shown in a disengaged position.

Referring now to the drawing, a fractional horsepower electric motor,such as that disclosed in patent application Serial No. 701,797, by IraM. Hurst entitled Electric Motor, now Patent No. 3,041,487, is generallyindicated by numeral and partially shown in outline. The motor has agear train mechanism or device 12 embodying the instant inventionmounted on the shaft end of the motor. The device 12 is mechanicallyconnected to the motor in a driving relation. An electromagnetic relay14 is mounted on the side of the motor in operable engagement with thegear train mechanism, as will be described hereinafter. The relay 12 maybe connected in ice parallelwith the motor, but for faster response themotor is allowed to run continually and the delay energized, orde-energized for output shaft rotation.

The gear train mechanism 12, which is a specific'embodiment of theinstant invention, includes a supporting frame consisting of an innerplate 16 and an outer plate 18, both of which are generally triangular,and three posts 20 which are riveted to the plates and hold'the platesparallel and spaced apart, as may be clearly seen in FIGURES l and 2.The base of the device is secured to the shaft end of electric motor 10by a conventional means.

The electric motor 10 has an output shaft 22 which extends through anopening 24 inthe inner plate. The outputshaft 22 has a drive pinion 26fixed on the end thereof, which drive pinion meshes with a drive gear 28to provide a speed reduction since the drive gear has a larger number ofteeth than the pinion 26. The drive gear 28 is press fitted on a gearbushing 30 which is in turn rotatably mounted on a clutch shaft 32. Theclutch shaft 32 is rotatably mounted in inner and outer plates 16 and18, respectively, and is parallel to the output shaft 22.

Bushing 30 is positioned adjacent to the inner plate 16 with a sleeve 34mounted on the clutch shaft 32 between bushing 30 and plate 16. A firstcircular sheet metal member 36 is also press fitted on the bushing 30coaxial of the clutch shaft so that the member 36 rotates with drivegear 28 and is journaled on the clutch shaft. The circular member 36 hasa flat circular portion about the center thereof and disposed inabutment with one surface of the drive gear 28. The perimeter of themem- 'ber has a plurality of outwardly extending pointed identical teethextending at equal intervals thereabout'and disposed at an angle to theplane of the drive gear no greater than a right angle. A second circularsheet metal member 38, which is identical to the first member 36 has aplurality of pointed teeth which mate with the teeth of the firstcircular member 36. The second circular member 38 is press fitted on oneend of a cylindrical actuator 40 for rotation therewith about the clutchshaft 32 with the fiat portion normal to the shaft and the teethextending therefrom toward the teeth of the first circular member. Themembers 36 and 38 and associated partsfrom a modified jaw clutch. Theactuator 40 includes an integral cylindrical housing 42 which iscoaxially journalled about the clutch shaft 32 and supports the member38. A circularactuator brake flange 44 is formed integral with the endof the housing opposite member 38. In order to provide a driving meansfor the housing 42, an internal gear with a plurality of teeth is cutaxially through the center of the housing, the teeth of the internalgear being parallel to the shaft 32 in the manner of splines. Theactuator 40 includes a spring disc 48 which is press fitted intoengagement with the internal gear 46 adjacent to member 38 and a helicalspring 50 is mounted within the housing in engagement with disc 48. Oneend of the interior of housing 42 is closed by the disc 48, while theother end is also closed by a gear which serves as a spline 52 whichengages the coil spring 50 so that the spring is compressed between thedisc 48 and the gear 52. Clutch shaft 32 is press fitted into gear 52 sothat the gear 52 rotates with the shaft 32. The gear 52 mates with theinternal gear 46 and the housing 42 rotates with shaft 32; however, thehousing may slide relative to gear 52 but rotates therewith.

A stop disc 54 of greater diameter than the spline 52 is press fittedonto the shaft 32 adjacent to the spline 52. Thus, the flanged end ofhousing 42 may slide into engagement with the stop disc 54 and bestopped thereby. At the other end, the axial movement of the housing islimited by bevel gear 36. However, the coil spring 50 reacting betweenthe spline52 and the spring disc 48 spring biases the flanged end of thehousing away from the disc 54 and the two members 36 and 38 inengagement.

A pinion 56 is press fitted on shaft 32 in engagement with the stop disc54. The pinion 56 in turn meshes with a takeoff gear 58 for a furtherspeed reduction since the pinion 56 has a smaller number of teeth thanthe meshing takeoff gear. The takeoff gear 58 is fixed to a take offshaft 60, which takeofl" shaft is rotatably mounted in the outer plate18 parallel to the shaft 32. The takeoff shaft has a splined end 62which provides a convenient means for attaching the takeoff shaft to adriven member which is not shown.

- The actuator 40 is engageable with a pivotally mounted actuator arm 64which is bifurcated at one end to form a pair of tangs 65 for frictionalengagement with flange 44 of the actuator 40. The end of the arm 64opposite the bifurcated end has a pair of cars 66 which extend outwardlyfor reasons which will become apparent hereinafter, and a tab 68 whichis integral with the cars 66 and is substantially perpendicular to thecars 66 and arm 64, as may be seen in the drawing. The bifurcatedactuator arm is pivotally supported by an integral arm support 70. Armsupport 70 includes a base 72 which is riveted to plate 16 and a pair ofposts 74 which each have a hook 76 formed therewith. Each of the hooks76 engage one of the cars 66 and pivotally support the bifurcated arm64. Thetab 68 of the bifurcated arm is engaged by a stem 78 which is anactuating portion of the relay 14. Thus, it is clear that when stem 78is extended to force inward tab 68, the bifurcated arm pivots about hook76 to engage the flange 44 thereby compressing spring 50 and disengagingthe two members 36 and 38.

The operation of the motor, gear train, clutch and brake assembly may bedescribed as follows. When current is supplied to the electric motor 10,the drive shaft 22 rotates with its pinion 26. The pinion 26, whichmeshes with drive gear 28 to provide a first speed reduction, turns thedrive gear but at a slower speed than the pinion 26. Inasmuch as member36 is mounted on the same bushing 30 as drive gear 28, the memberrotates at the same speed as drive gear 28. When members 36 and 38 arein engagement, the member 38 rotates at the same speed as member 36,and, of course, housing 42 also rotates with member 38. Since gear 52mates with the internal gear 46, the housing shaft 32 which receives thegear 52, also rotates at the same speed as bushing 30. The shaft 32 hastakeoff pinion 56 press fitted thereon, so that the pinion 56 rotates atthe same speed as the shaft 32. The takeoff pinion in-turn meshes withtakeoff gear 58 which is fixed on takeoff shaft 60. It is, of course,clear that there is a speed reduction between the takeoff pinion 56 andtakeoff gear 58.

When it is necessary to stop the output of the device,

the current is cut off to the electric motor so that the.

shaft 22 would stop if it were not for inertia. When the current is cutoff to the motor 10, the same source of current, which is not shown,also cuts off the current to the relay 14, so that a spring (not shown)in the relay urges the stem 78 toward the shaft 32. The stem 78 engagestab 68 to pivot the actuator arm 64 about thesupport 70 so that tangs 65are in frictional engagement with flange 46. The pivoting of arm 64slides the housing along actuator gear 52 into engagement with disc 54against the force of coil spring 50 so that cup shaped members 36 and 38are disengaged. Thus, the motor is disconnected from the takeoff shaftinasmuch as the cup shaped members are disconnected.

After power is cut off, the force between the bifurcated arm 64 and theflange 44 is limited to force exerted by spring 50, and hence the metalto metal contact of the bifurcated arm 64 and flange .44 provides littlebraking force. During this period the two members 36 and 38 tend torotate at approximately the same rate, since mem- 'ber 36 is subjectedto deceleration of the motor 10 and member 38 is subjected to therelatively slight braking action of the bifurcated arm 64 and flange 44in opposition to the inertia of the load. Hence, at the moment the cupshaped members 36 and 38 are separated, there is little torque betweenthe members, and the members are not subject to substantial Wear.However, once the housing 42 engages the stop disc 54, the force exertedon the flange increases, since coil spring 50 no longer limits thisforce. The braking action on the takeoff shaft and any driven deviceattached to the shaft after the housing 42 engages the stop disc-54 bymeans of the friction developed between the tangs of the bifurcated arm64 and flange 44, producing extermely rapid stoppage of the drivendevice.

Many other and additional advantages of this construction will beapparent to those skilled in the art. It is therefore intended that thescope of the present invention be not limited by the foregoingdisclosure, but rather only by the appended claims.

The invention claimed is:

1. A clutch and brake assembly comprising, in combination, a base, aclutch shaft rotatably mounted on said base, a first member rotatablyjournaled about the clutch shaft and a second member translatably androtatably journaled about the clutch shaft and adapted to engage thefirst member, said second member having a housing mounted thereon andextending coaxially therefrom on the side thereofremote from the firstmember, said housing having a cylindrical cross section and a flangeextending outwardly therefrom remote from the first member, a springdisposed about the clutch shaft within the housing urging the twomembers into engagement, a spline having a cylindrical body coaxiallydisposed about said clutch shaft and secured thereon on the side of thesecond member opposite the first member, said spline having a pluralityof spaced ridges extending from the body thereof, said housing having acoaxial recess therein with spaced parallel grooves therein mating withthe ridges of the spline, a disc of larger diameter than the spline.mounted coaxially on the clutch shaft adjacent to the spline and on theside therefrom opposite the first member, said spline being restrainedfrom movement along the axis of the shaft and the housing beingtranslatable on the shaft into abutment with the disc, translation ofsaid housing translating the second member from the first member, anactuator arm comprising a fiat sheet having a semicircular recess at oneend, means for mounting the arm with said end confronting thecylindrical portion of the housing and adapted to abut the flange, saidmounting means having a pivotal axis normal to the clutch shaft andspaced from the circular end thereof, and electromechanical means fordriving the arm into abutment With the flange of the housing totranslate the housing into abutment with the disc against the tension ofthe spring, whereby the clutch and brake assembly may be mounted on anelectric motor and the electromechanical means electrically connected tothe electric motor for actaution on deactuation of the electric motor.

2. A clutch and brake assembly for an electric motor comprising theelements of claim 1 in combination with a gear rotatably mounted on saidclutch shaft and secured on the first member, said gear being adapted tomesh with a gear mounted on the driving shaft of the electric motor.

3. A clutch and brake assembly for an electric motor comprising theelements of claim 1 wherein .the first and second members of the clutchcomprise a pair of cupshaped sheet members having teeth at theirperipheries, the peripheries of the cup-shaped sheet members havingapproximately the same diameter and confronting each other, the teeth ofone member being at an angle no greater than a right angle to theconfronting teeth of the other member and being adapted to engage theteeth of the other sheet member.

4. An assemblage of an electrical motor, a clutch, and a brakecomprising, in combination, an electric motor, a base mounted on theelectric mot-or, a clutch shaft rotatably mounted on said base, a firstmember rotatably journaled about the clutch shaft and a second membertranslatably and rotatably journaled about the clutch shaft and adaptedto engage the first member, said second member having a housing mountedthereon and extending coaxially therefrom on the side thereof remotefrom the first member, said housing having a cylindrical cross sectionand a flange extending outwardly therefrom re- \mote from the firstmember, a spring disposed about the clutch shaft within the housingurging the two members into engagement, a spline having a cylindricalbody coaxially disposed about said clutch shaft and secured thereon onthe side of the second member opposite the first member, said splinehaving a plurality of spaced ridges extending from the body thereof,said housing having a coaxial recess therein with spaced parallelgrooves therein mating With the ridges of the spline, a disc of largerdiameter than the spline mounted coaxially on the clutch shaft adjacentto thespline and on the side thereof opposite the first member, saidspline being restrained from movement along the axis of the shaft andthe housing being translatable on the shaft into abutment with the disc,translation of said housing translating the second member from the firstmember, an actuator arm comprising a flat sheet having a semicircularrecess at one end, means for mounting the arm with said end confrontingthe cylindrical portion of the housing and adapted to abut the flange,said mounting means having a pivotal axis normal to the clutch shaft andspaced from the circular end thereof, the electric motor having anoutput shaft mechanically coupled to the first member, andelectromechanical means electrically connected to the motor for drivingthe arm into abutment with theflange of the housing to translate thehousing into abutment with the disc against the tension of the spring,said electromechanical means being actauted on deactuation of theelectric motor.

References Cited by the Examiner UNITED STATES PATENTS DAVID J.WILLIAMOWSKY, Primary Examiner.

4. AN ASSEMBLAGE OF AN ELECTRICAL MOTOR, A CLUTCH, AND A BRAKECOMPRISING, IN COMBINATION, AN ELECTRIC MOTOR, A BASE MOUNTED ON THEELECTRIC MOTOR, A CLUTCH SHAFT ROTATABLY MOUNTED ON SAID BASE, A FIRSTMEMBER ROTATABLY JOURNALED ABOUT THE CLUTCH SHAFT AND A SECOND MEMBERTRANSLATABLY AND ROTATABLY JOURNALED ABOUT THE CLUTCH SHAFT AND ADAPTEDTO ENGAGE THE FIRST MEMBER, SAID SECOND MEMBER HAVING A HOUSING MOUNTEDTHEREON AND EXTENDING COAXIALLY THEREFROM ON THE SIDE THEREOF REMOTEFROM THE FIRST MEMBER, SAID HOUSING HAVING A CYLINDRICAL CROSS SECTIONAND A FLANGE EXTENDING OUTWARDLY THEREFOM REMOTE FROM THE FIRST MEMBER,A SPRING DISPOSED ABOUT THE CLUTCH SHAFT WITHIN THE HOUSING URGING THETWO MEMBERS INTO ENGAGEMENT, A SPLINE HAVING A CYLINDRICAL BODYCOAXIALLY DISPOSED ABOUT SAID CLUTCH SHAFT AND SECURED THEREON ON THESIDE OF THE SECOND MEMBER OPPOSITE THE FIRST MEMBER, SAID SPLINE HAVINGA PLURALITY OF SPACED RIDGES EXTENDING FROM THE BODY THEREOF, SAIDHOUSING HAVING A COAXIAL RECESS THEREIN WITH SPACED PARALLEL GROOVESTHEREIN MATING WITH THE RIDGES OF THE SPLINE, A DISC OF LARGER DIAMETERTHAN THE SPLINE MOUNTED COAXIALLY ON THE CLUTCH SHAFT ADJACENT TO THESPLINE AND ON THE SIDE THEREOF OPPOSITE THE FIRST MEMBER, SAID SPLINEBEING RESTRAINED FROM MOVEMENT ALONG THE AXIS OF THE SHAFT AND THEHOUSING BEING TRANSLATABLE ON THE SHAFT INTO ABUTMENT WITH THE DISC,TRANSLATION OF SAID HOUSING TRANSLATING THE SECOND MEMBER FROM THE FIRSTMEMBER, AN ACTUATOR ARM COMPRISING A FLAT SHEET HAVING A SEMICIRCULARRECESS AT ONE END, MEANS FOR MOUNTING THE ARM WITH SAID END CONFRONTINGTHE CYLINDRICAL PORTION OF THE HOUSING AND ADAPTED TO ABUT THE FLANGE,SAID MOUNTING MEANS HAVING A PIVOTAL AXIS NORMAL TO THE CLUTCH SHAFT ANDSPACED FROM THE CIRCULAR END THEREOF, THE ELECTRIC MOTOR HAVING ANOUTPUT SHAFT MECHANICALLY COUPLED TO THE FIRST MEMBER, ANDELECTROMECHANICAL MEANS ELECTRICALLY CONNECTED TO THE MOTOR FOR DRIVINGTHE ARM INTO ABUTMENT WITH THE FLANGE OF THE HOUSING TO TRANSLATE THEHOUSING INTO ABUTMENT WITH THE DISC AGAINST THE TENSION OF THE SPRING,SAID ELECTROMECHANICAL MEANS BEING ACTUATED ON DEACTUATION OF THEELECTRIC MOTOR.